1. Field of the Invention
The present invention relates to a continuous feeding body of dampers for use in suspensions for supporting electric/electronic parts, particularly magnetic heads for magnetic recording media, optical pickups for optical recording media, etc.
The present application is based on Japanese Patent Application No. 2000-108141, which is incorporated herein by reference.
2. Description of the Related Art
A magnetic head inside a hard disk drive unit floats above a magnetic disk while keeping a very small gap by use of the balance between the wind pressure generated by the revolution of the magnetic disk and the spring elasticity of a suspension for supporting the magnetic head. In recent years, such a hard disk drive has been made higher in recording density and higher in speed. The gap between the magnetic head and the magnetic disk has been narrower to increase the recording density. In addition, the rotation speed of the magnetic disk has been larger to respond to the higher speed of the hard disk drive. Vibration is generated in the suspension due to wind turbulence caused by the revolution of the magnet disk so that the positioning accuracy of the magnetic head attached to a top end portion of the suspension is lowered conspicuously. Recently, such a tendency has made the problem of vibration more serious.
On the other hand, also in an optical disk drive, in accordance with higher recording density and higher disk rotation speed, there has been considered a method in which a suspension is used in place of a conventional gimbal spring to support an optical pickup, in the same manner as the suspension of the hard disk drive unit. Thus, the problem of vibration has been produced in the same manner.
As one of methods for suppressing the vibration of a suspension, there is a method in which a damper constituted by a vibration damping material layer (viscoelastic body) and a restraint member (restraint body) in contact with the vibration damping material layer is provided on the suspension, as disclosed in Japanese Patent Publication No. JP-A-59-180855. FIG. 9 shows a state where such a damper 3 is pasted on a suspension 22 of a magnetic head 21. Incidentally, the reference numeral 23 represents an attachment block for fixing the suspension 22.
For example, a viscoelastic body as disclosed in Japanese Patent Publication No. JP-A-5-132658 is used for the vibration damping material layer. On the other hand, it has been known that a polyimide film disclosed in Japanese Patent Publication No. JP-A-10-249865 or other plastic films such as a polyester film, etc. as well as metal foil of stainless steel or the like may be used for the restraint body.
In such a damper constituted by a restraint body and a viscoelastic body, the viscoelastic body fixed by a coated substrate of a suspension or the like and the restraint body produces shear deformation when vibration is generated. By using that heat is generated by this deformation, the damper transduces vibration energy to heat energy so as to suppress the vibration.
Such a damper is provided in a form that a laminated body on which the restraint body and the viscoelastic body are pasted is punched out by a die. Since the viscoelastic body usually has tackiness itself, the viscoelastic body is supplied in a condition that the opposite surface to the surface where the restraint body has been laminated is pasted to a liner subjected to release treatment. Then, the damper is usually separated from the liner for use at the time the damper is pasted on a part serving as a suspension or the like.
Such a damper is usually pasted manually on a suspension or the like. In this manner, however, it is difficult to paste the damper accurately on predetermined position, and position deviation often takes place. If the position on which the damper is pasted is deviated, there arises a problem that an expected vibration damping property cannot be obtained.
In addtion, when the damper is manually pasted, the time to paste one damper is so long that many workers have to be cast for mass production. Further if the damper is manually pasted, the damper of the suspension or the like is exposed to contamination generated from human bodies. That is very inconvenient particularly if the damper or the suspension or the like is used for applications such as a hard disk where breakdown may be occurred by contamination.
Taking the foregoing problems into consideration, it is an object of the present invention to provide a damper continuous feeding body which allows dampers to be pasted by an automatic machine so as to improve the accuracy in pasted Position of the dampers and enhance the efficiency in pasting, and further whereby the dampers can be prevented from being exposed to contamination.
The aforementioned object can be attained by the present invention as follows.
That is, according to the present invention, there is provided a damper continuous feeding body, comprising a plurality of punched out dampers, each of which is constituted by a viscoelastic body and a restraint body which are laminated on each other, wherein surfaces of the viscoelastic bodies are pasted on a release surface of a continuous liner so that the plurality of dampers are arranged at a predetermined pitch.
In the above damper continuous feeding body, preferably, the pitch with which the dampers are arranged is substantially equal to a pitch with which the dampers are punched.
Preferably, portions of the liner on which the dampers are pasted are punched into the same shape as that of the dampers while a backing tape is pasted on portions surrounding the punched portions so as to hold the punched portions.
More preferably, the liner is wound on a reel, and more preferably, a plastic film is rolled in as an interleaf when the liner is wound on the reel.
Preferably, the reel is subjected to antistatic treatment so that surface resistivity thereof is not higher than 1011 xcexa9/xe2x96xa1. Preferably, a foam layer is formed on an outer circumferential side of a core portion of the reel.
According to the present invention, a plurality of dampers are arranged at a predetermined pitch on a release surface of a continuous liner in the condition that the dampers have been formed by punching. Thus, the dampers can be pasted by an automatic machine. Then, since the surface of a viscoelastic body is pasted, pasting can be performed by use of the tackiness of the viscoelastic body. In addition, the exposed portion of the viscoelastic body is reduced so that contamination can be reduced. As a result, the pasted position accuracy of the dampers can be improved by the automatic machine, and the pasting can be performed efficiently. Further, it Is possible to prevent the dampers from being exposed to contamination.
In addition, if the pitch with which the dampers are arranged is substantially equal to the pitch at which the dampers have been punched, the dampers can be arranged at a predetermined pitch by use of the punching pitch as it is. Thus, it is possible to omit a troublesome process in which the dampers are rearranged after they are punched.
When the portions of the liner where the dampers have been pasted are punched in the same shape as the dampers and held by a backing tape pasted on portions surrounding the punched portions, the dampers can be punched together with the liner. Accordingly, the punching process becomes easy. In addition, the liner used for the punching can be used as it is, and further the arrangement of the dampers when they are punched can be utilized as it is, as described above. In addition, because the dampers are held by the backing tape pasted thus, the dampers are hardly left out, and can be separated from the liner easily.
If the liner is wound on a reel, an elongated liner on which the dampers are pasted can be continuously supplied from the reel. It is therefore possible to enhance the workability in the automatic machine.
If the liner on which the dampers are pasted is rolled in as it is, when a plastic film is rolled in as an interleaf the dampers will be apt to deviate in position due to the winding-tightening force. On the contrary, if a plastic film is rolled in together as an interleaf, a slip property can be obtained between the dampers and the interleaf of the plastic film. Thus, the dampers can be preferably from positional deviation.
If the reel is subjected to antistatic treatment so that the surface resistivity thereof becomes not higher than 1011 xcexa9/xe2x96xa1, release electrification generated between the reel and the liner when the liner is drawn out can be suppressed. Thus, dust or foreign matters in the air can be effectively prevented from adhering to the liner. In addition, head crush in an MR head or the like can be made difficult to occur.
If a foam layer is formed on the outer circumferential side of a core portion of the reel, the winding-tightening force particularly on the inner circumferential side where the winding-tightening force increases can be relieved by the compression deformation of the foam layer. Thus, the dampers can be effectively prevented from positional deviation on the outer circumferential side.